Tax · Return for 2026 income
Tax return 2027: where to copy each amount from your forms?
Updated on
Since 1 November 2026, withholding tax on pay has been calculated differently (Royal Decree of 27 September 2026). The calculations on this page still follow the previous rules: for pay received from 1 November, withholding tax and net pay may differ. Update in progress.
The amount in code 250 of your tax form 281.10 (fiche 281.10), i.e. your pay, goes in code 1250 of the tax return, and the amount in code 286 (withholding tax) in code 1286; for your partner, the codes start with 2 (2250, 2286). The return for 2026 income will be filed in spring 2027; the official dates have not been published yet.
Copy the amounts from your forms and certificates below: Indexo shows the code for each one, explains the heading and simulates the result, so you can check the proposed simplified return before accepting it. Nothing is transmitted: you stay in control of your tax return.
Which amount in which code?
The tax return code repeats the form code, preceded by a 1 for partner 1 and a 2 for partner 2. Regional reductions start with 3 and 4. The two digits after the dash are check digits, printed on the paper return.
| Document | What it is | Tax return code | Section | Reliability |
|---|---|---|---|---|
| 281.10, code 250 | Pay (salaries, wages, holiday pay, year-end bonus) | 1250-11 (partner 2: 2250-78) | IV, A, 1, a | explanatory notes or official form |
| 281.10, code 251 | Early holiday pay (departure holiday pay) | 1251-10 (partner 2: 2251-77) | IV, A, 3 | explanatory notes or official form |
| 281.10, code 252 | Pay arrears | 1252-09 (partner 2: 2252-76) | IV, A, 4 | explanatory notes or official form |
| 281.10, code 308 | Payments in lieu of notice (notice not worked) and redeployment allowances | 1308-50 (partner 2: 2308-20) | IV, A, 5 | explanatory notes or official form |
| 281.10, code 247 | December pay paid by a public authority | 1247-14 (partner 2: 2247-81) | IV, A, 6 | explanatory notes or official form |
| 281.10, code 254 | Employer contributions to commuting | 1254-07 (partner 2: 2254-74) | IV, A, 7, a | explanatory notes or official form |
| 281.10, code 284 | Work bonus (reduction of employee contributions), basis for the fiscal work bonus | 1284-74 (partner 2: 2284-44) | IV, K | to be confirmed |
| 281.10, code 285 | Deductions for a supplementary pension (group insurance) | 1285-73 (partner 2: 2285-43) | IV, F | to be confirmed |
| 281.10, code 286 | Withholding tax deducted | 1286-72 (partner 2: 2286-42) | IV, H | secondary source |
| 281.10, code 287 | Special social security contribution deducted | 1287-71 (partner 2: 2287-41) | IV, I | to be confirmed |
| Dividends | Withholding tax on investment income deducted from the first exempt tranche of dividends (recoverable) | 1437-18 (partner 2: 2437-85) | VII | secondary source |
| 281.60 | Pension savings (certificate 281.60) | 1361-94 (partner 2: 2361-64) | X, E | secondary source |
| 281.86 | Childcare expenses (certificate 281.86) | 1384-71 (partner 2: 2384-41) | X, B | secondary source |
| Donation receipt | Donations to approved institutions | 1394-61 (partner 2: 2394-31) | X, A | secondary source |
| 281.81 | Service vouchers in Wallonia: number of vouchers bought | 3366-29 (partner 2: 4366-96) | Regional part (Wallonia) | secondary source |
| Bank certificate | Chèque habitat (Walloon housing tax credit): interest and capital on a loan taken out since 2016 (before the income year) | 3324-71 (partner 2: 4324-41) | IX (Wallonia) | to be confirmed |
| Bank certificate | Chèque habitat: mortgage protection insurance premiums on the same loan | 3325-70 (partner 2: 4325-40) | IX (Wallonia) | to be confirmed |
| Bank certificate | Walloon regional housing bonus (woonbonus / bonus logement) (loans taken out before 2016) | 3370-25 (partner 2: 4370-92) | IX (Wallonia) | to be confirmed |
| Bank certificate | Long-term savings: capital on a loan for another home (signed before 2024) | 1358-97 (partner 2: 2358-67) | X (federal) | to be confirmed |
Pensions (tax form 281.11), sickness and invalidity benefits (281.12) and unemployment benefits (281.13) have their own codes, in section IV, B and C (unemployment, sickness) and section V (pensions). The form shows the code to use.
Your tax return step by step
- Gather your documents: forms 281.10 from each employer (before 28 February), 281.11 for a pension, 281.12 or 281.13 for benefits, certificates 281.60 (pension savings), 281.86 (childcare), donation receipts, the bank certificate for your mortgage loan.
- Open Tax-on-web in MyMinfin: most amounts are already filled in. Compare them with your documents, code by code, rather than retyping everything.
- Add what is missing: expenses the tax authorities do not know about, family situation on 1 January 2027, actual expenses if you choose them.
- Simulate the result with the tool on this page or the household tax simulator, then with the Tax-on-web calculation before you submit.
Checking the proposed simplified return
Nearly half of taxpayers receive a proposed simplified return. If it is correct and complete, you have nothing to do: you will receive the tax assessment notice (aanslagbiljet / avertissement-extrait de rôle). If not, correct it in Tax-on-web or on paper, within the same deadlines as a normal return.
The tax authorities do not always have all your certificates. Check in particular:
- childcare expenses, donations, service vouchers and pension savings;
- your family situation and your dependent children on 1 January;
- the recoverable withholding tax on dividends (code 1437);
- an old mortgage loan: the Region and the year of the loan determine the benefit;
- conversely, a second home or foreign income not included, which will increase the tax.
Enter the amount stated in the proposal in the tool: if it differs from the simulation by more than €50, the tool flags it.
Copy your forms and check the result
Copy the amounts from your 281 forms and your certificates for 2026 income. Indexo shows the code for each one and simulates the tax. Nothing is transmitted.
The tool could not be displayed. Reload the page (Cmd + Shift + R on a Mac, Ctrl + F5 on a PC).
Frequently asked questions
When do you need to fill in the return for 2026 income?
In spring 2027, when Tax-on-web opens. The deadlines (paper, Tax-on-web, authorised representative) have not been published yet: Indexo will add them as soon as FPS Finance publishes them.
Does Tax-on-web automatically include my tax form 281.10 (fiche 281.10)?
Usually yes: your employer files the form in Belcotax by 28 February at the latest, and its amounts appear in Tax-on-web. Check them anyway, especially if you had several employers, a corrected form or a payment in lieu of notice.
What do the two digits after the dash mean, as in 1250-11?
They are check digits, which prevent copying errors on the paper return. In Tax-on-web, only the four-digit code counts.
Does Indexo send my tax return?
No. Nothing is transmitted: Indexo does not fill in your return for you. It helps you find the right code and check the result before you send your return or accept the proposal.
What next?
- Household tax simulatorAll household income, line by line.
- Tax form 281.10 explainedEach code on your tax form, compared with a simulation.
- Actual expenses or lump sum?The choice to make in your tax return.
- Annual pay reviewYour 12 payslips compared with tax form 281.10.
Sources
Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.
- Notice explicative de la déclaration à l’impôt des personnes physiques, partie 1, Région wallonne, exercice d’imposition 2026 (revenus 2025), FPS Finance.
- IPP, cadre IV : revenus professionnels (15 mai 2026): code 1250 (salary from tax form 281.10) and code 1286 (withholding tax), Billy (secondary source).
- IPP, cadre X : réductions d’impôt (19 May 2026): certificates 281.60, 281.86, 281.81, Walloon service vouchers codes 3366 and 4366, Billy (secondary source).
- IPP, cadre VII : revenus mobiliers (18 May 2026): €833 of dividends and €1,020 of regulated savings interest exempt, codes 1437, 1160, 1162, Billy (secondary source).
- Une déclaration qui rapporte : voici les avantages fiscaux à ne pas oublier (1 July 2024): codes 361, 364, 366, 384, 394 and 1437, Forum for the Future (secondary source).
- Fiches fiscales 2021 : explication de la fiche 281.10, zone par zone (updated on 30 April 2021), FPS BOSA. Cross-checked with: a tax form 281.10 for 2024 (codes 250, 252, 254, 286 and 287).
- Tax form 281.10 for 2024 income published under the transparency of mandates rules: items 6 (code 250), 7b (252), 14 (254), 23 (286) and 24 (287), Municipality of Watermael-Boitsfort.
- Avantages fiscaux pour les emprunts hypothécaires en Région wallonne (codes 3324, 3325, 3338, 3339, 3370, 1358), FPS Finance, circular 2024/C/26 (as reproduced by Forum for the Future) (secondary source).
- Votre déclaration est pré-remplie : est-elle complète ? (updated on 5 January 2026), Wikifin (FSMA) (secondary source).
- Fiches fiscales revenus 2025 : Belcotax est disponible (10 February 2026), filing by 28 February, Securex (secondary source). Cross-checked with: billy.tech (26 September 2026).
- Récapitulatif des principaux plafonds fiscaux, exercice d’imposition 2027 – revenus 2026 (23 December 2025), Wolters Kluwer (secondary source).
- Épargne-pension 2026 : 2 200 contribuables piégés par le double plafond, OECCBB (secondary source).